Prep Herbs: In a small bowl, add the thyme, oregano, and parsley and mix.
Saute Aromatics: Heat a small saute pan over medium heat and add olive oil. Add onion and celery and teaspoon of salt and saute for 2 minutes. Add garlic and 2 teaspoons of the spice mixture and saute for another minute, stirring often.
Slow Cook: Add sauteed onions and celery to the crock pot. Then add potatoes, carrots, and corn, remaining thyme, oregano, parsley, salt, plus the ground mustard, celery salt, black pepper, and soy sauce. Add the stock. Slow cook on high for 3-4 hrs or low for 5-6 hrs.
Finish: In the final 10 minutes, add the spinach and lemon juice.
Serve and Enjoy: Serve with your favorite crusty bread or soft rolls!